Acoustic compensator



g- 9, 1932 B. R. HUBBARD 1,870,569

ACOUSTIC COMPENSATQR Filed Oct. 31. 1929 2 Sheets-Sheet 1 In Vefifor e 1 Beverly R. Hubbard lffofney 9, 1932- B. R. HUBBARD ACOUSTIC COMPENSATQR 2 Sheets-Sheet. 2

Filed Oct. 31. 1929 Figure 3 Fz'yure 4 In ve n t o r B6 var/y R, [ll/Marv y $11 M mpg/ A Patented Aug. 9, 1932 NITED STATES PATENT OFFC BEVERLY R. HUBBARD, OF MELROSE, MASSACHUSETTS, ASSIGNOB TO SUBMARINE SIGNAL COMPANY, OF BOSTON, MASSACHUSETTS, A CORPORATION OF MAINE acousric comrmvsa'ron Application filed use... 31, 1929. serial mi. 403,169.

The present invention relates to compensa-' tor constructiomin particular to the type used to locate the direction of a source of sound. 1

In systems in which compensators are used, the general type described in the present invention has been 'use dfor a considerable time. In this type, the'soundenergy is transmitted by means of sound receivers or translating devices to the compensator, where the sound travels over air passages to the ears of the observer. The air passa es in compensators of this type are formed y two plates, one of which is grooved and the other flat. The flat plate is provided with stopping blocks fitting in the grooves which. are used to shorten or lengthen the elieetive length of the grooves when the top grooved plate is rotated. The inlets and outlets of the sound passages are located in the lower flat plate in position to communicate with the grooves, so that there is a continuous open passage from the inlet of sound to the outlet. The passage in the compensator is formed by the groove and the plate, which fit closeto one another and are always carefully I fitted by skilled workmen.

In spite of this care 'whlch is exercised in the construction of compensators, I have found that as the upper plate is moved over the lower plate in making a setting on the instrument, there is considerable rubbing which wears the material and creates an abrasive means when mixed with the oil effect and correcting it, I have been a le to construct a compensator which is more efficient than those previously used, particularly after the com nsator has been in use for some time. I ave, found that. in this connection a slight air leak hampers great- I 'ly the efiective operation.

The features of the compensator will be more fully understood from a consideration of the embodiment described below in connection with the drawings annexed hereto in which Figure 1 shows a sectional view of the compensator, Figure 2 shows a detail in section,

Figure 2a shows diagrammatically the arrangement of the sound passages in the compensator,

Figure 3 shows a detail, and

Fi re 4 shows another view of the detail of F1 ure 3.

In igure 1 the compensator is shown vertical, for convenience, but it is always operated horizontally with the hand wheel 1 in a horizontal position.

The compensator proper is composed of two parallel plates 2 and 3, which are made to abut one another on their plate surfaces. The top plate 2 is made fast to the housing 31 of the hand wheel, which housing is sup ported by a ball bearing 4 resting on the stationa shaft 5. When the hand wheel 1 is turne therefore, the plate 2 is turned with it about the shaft 5 as a center.- The shaft 5 has a collar 6 to prevent the hand wheel and shaft from being pulled upwards.

The top plate 2 is provided with grooves 7, 8, 9, 10 and 11, through which the sound is conducted. The sound is conducted throu h the bottom plate from the receivers,

one 0 which is shown at 12, to the passages 7 and 8 through inlets in the lower plate. The smaller passages 7 and 8 are connected to the larger passages 9, 10 and 11 by means of I the curved pipes 13 and 14.

As the invention is not concerned with thearrangement of the'sound passages, these are only briefly described, sincethey may be ar-- ranged in any well known way of theprior art.

The lower plate 3 is provided as shown in Figure 2 with blocks 15 and 16, whichare located on the outer side of the outlets to the receiving tubes, one of which is shown at 17 in Figure 1.

The compensator is supported in a casing 18, by m'eansof the top cover 32, which is fixed to the lower plate through the bracket 19, forming a part of the plate. The bracket 19 is so formed that there is a groove 20 between it and the outer wall edge of the plate 2, which groove is cut lower than the plate 3 and is provided with a hole 21 for the oil to drain out. When the two plates rub against one another, the tendency is for the small loosened particles to be sent outwards into the groove 20, where they fall down and cannot get back under the edge of the plate. The oil, at the same time, is drained off.

The arrangement of the sound passages will be more clearly understood from Fig. 2a which shows the arrangement of a socalled'four-spot unit having four receiving transmitters 40, 41, 42 and 43 which may be connected to one or a number of hydrophones V or magnetophones located. in the water on a a framework or tripod or in the skin of a vessel. The sounds received on the receivers 40 and'41 are conducted throughthe tubes 44 and 45, respectively, to the smaller passages 7 and 8. A stop 48 is provided between the points where the tubes 44 and 45 enter the compensator so that the sound from the receiver 40 will follow along the passage 7 and the sound from the receiver 41 will follow along the passage 8. The soundsv following along the passages 7 and 8 meetin the larger sound passage opening 49 and the two sounds are conducted through the pipe 13, shown in dotted lines in Fig. 2a, to the larger comensating passage 10. Similarly, the sounds rom the receivers 42 and 43v are conducted respectively over the paths 51 and 52 to the small compensating paths 53 and 54, respectively, which are joined at the sound passage opening 55. The sounds from this 0 ening are conducted over the tube 14, indicated by dotted lines, to the larger sound compensating passages 10. The passages 10 and 10 respectively connect to the'left ear piece 57 and the right ear piece 58 of the stethoscope tubes. The blocks 59 and 60 serve to prevent the intermingling of the sound passages in the larger compensating tubes. In the schematic view of the compensator shown in Fig. 2a the receivers, the inlet and outlet openings for the sound and the sound blocks as well as the stethoscope tubes, remain in a fixed position, the only thing moving being the upper compensator plate containing the three sound grooves.

The curved pipe 13 is also arranged so that it may be taken out and cleaned. This is done by removing the thumb nut 22, the clamping arm 23, and taking out the pipe 13, which simply rests in the shoulders 24 and 25 of the inlet passages 26 and 27.

In this way, the wearing dust or any dirt or oil may be removed fromthe pipe and prevented from returning to the inside of the compensator air passages to cause frictional wear.

another, means for rotating oneof said plates with respect to the other, a sound groove in 'one of said plates and a groove just exterior to the bearing surface of the plates positioned lower than the plates and extending substantially about the periphery thereof.

2. An acoustic compensator of the type described including two parallel opposed plates positioned to bear against one another and having sound passages therein, a casing, means for supporting the compensator in the casing from the vlower plate and groove, means outside the bearing surface adjacent the lower plate for receiving the wearing dust from between the bearing surfaces.

3. An acoustic compensator of the type described including a casing, a plurality of plates having bearing surfaces between them forming enclosed sound passages, means attached to the lower plate for positioning said plates horizontal in said casing and a groove extending about the lower plate exterior of the bearing surface for receiving the abrasive dust from the bearing surface between the plates.

4. In an acoustic compensator of the type 7 sages formed in saidplates, and means for connecting said sound passages including bent tubes connecting with openings in said plate and means for attaching or removing said benttubes, comprising a clamping means clamping said tube to said plate.

6. An acoustic compensator of the type described comprising a casing, a top cover resting on the edge of said casing, a plurality of sound plates having sound passages therein, positioned with their plate surfaces bearing on one another, the lower of said plates having integrally outwardly extending flanges and means for fixing said plate to said cover through said flanges.

In testimony whereof I affix my signature.

BEVERLY R. HUBBARD. 

